Vat for electro-metallurgy



Nov. 18, 1958 JEAN-CHARLES SIMON-SUISSE VAT FOR ELECTRO-METALLURGY Filed March 15, 1955 5 Sheets-Sheei'. 1

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VAT FOR ELECTRO-METALLURGY 5 Sheets-Sheet 3 Filed March 15, 1955 Nov. 18, 1958 JEAN-CHARLES SIMON-SUISSE 2,851,036

VAT FOR ELECTRO-METALLURGY Filed urch 15, 1955 5 Sheets-Sheet 4 Fad. 7

Nov. 18, 1958 JEAN-CHARLES SIMCN SUIS SE ,0

- VAT FOR ELECIRO-METALLURGY Filed March 15, 1955 5 Sheets-Sheet 5 Ame-M United States Patent Ofiice 2,861,036 I VAT FOR ELECTRO-METALLURGY Jean-Charles Simon-Suisse, Montbonnot, France, assignor, by mesne assignments, to Pechiney, Compagnie de Produits Chimiques et Electrometallurgiques, Lyon,

France, a French company Application March 15, 1955, Serial N 0. 494,516 Claims priority, application France March 29, 1954 6 Claims. (Cl. 204-243) The present invention relates to the construction of vats Qused in the electro-metallurgical industry, and especially to those vats of the kind which are used in the production of aluminium by electrolysis.

Vats of this kind are generally constituted by a metallic casingv which is internally lined with a suitable lining known as brasking. In the case of vats which are used in the preparation of aluminium by electrolysis, it is the brasking which forms the cathode or :anode, whilst at the same time it receives the bath of alumina and molten aluminium.

In the usual form of construction, the casing of these vats, formed by a bottom and four sides, has the appearance of a box open at its upper part. The bottom and the sides are stiffened by the types of reinforcement usually employed in metal construction work, so as to withstand both static stresses and the deformation which can be produced due to various causes.

Now it has been observed that in spite of the strength-' ening of the members of the vat, breaking or deformation frequently occurs and this is particularly serious since they sometimes result in the collapse of the bath. In

addition, whatever precautions may have been taken, the brasking contained in the vat rapidly deteriorates and it becomes necessary to replace-it frequently, and this constitutes'an unfortunate and .very costly drawback.

The present invention has for its object to overcome these drawbacks and to improve the performance and the life of these vats, both in respect of the metallic of the metallurgical processes. Whilst in the case of rigid vats of previous kinds, accidents frequently occur due to breaking of the brasking, such accidents are avoided with vats having walls with elastic displacements which can follow the deformation of the brasking without causing rupture of this latter.

In producing the vat in accordance with the invention,

the usual means of strengthening the vat, intended to render it capable of withstanding the stresses due to the transformation of the brasking, are eliminated. This results in a considerable reduction in weight and a substantial economy. As the dead weight is reduced, the supports may also be appreciably lighter. As'they no longerhave to withstand deformation, the value of which is*-"difiicult if not impossible to estimate, the elements may be exactly calculated as a function of perfectly wellknown stresses, without the excess of material which is usually'provided as a measure of safety.

elastic restor- The attached drawings show by way -of example' methods ofmanufacture of casings for vats used In the electrolysis of aluminium, in accordance with the nvention. V

' Fig. 1 is a diagrammatic-view inperspective of the general arrangement of the vat. V

- Fig. 2 is a half view in longitudinal cross section.

Fig. 3 is a half view in'transver'se cross-section. Fig. 4 shows in cross-section the details of the coupling of the sides of the elements with the baseof the vat.

Fig. 5 is a plan view corresponding'to; Fig. 4-. Fig. 6 is a longitudinal cross-section of an alternative form of embodiment. V

Fig. 7 is a transverse cross-section'of the alternative form shown in Fig. 6. i

Fig. 8 shows a longitudinal cross-section of a further form of embodiment.

Fig. 9 is an explanatory curve in connection-with the form of embodiment shown in Fig. 8. v

The vat in accordance with the invention, instead'of being formed by a casing in one single piece, is made up of elements or members which can have a certain relative movement with respect'to each other.

As shown diagrammatically in Fig. l, the metallic casing is composed of a flat member 1 which forms the base, {of longitudinal sides 2 andof transverse sides 3." These members are separate and -are placed one on the other without being assembled togetherin' arigidmanner.

They. are simply connected with means of attachment which leave a sufiicient degree of freedom to permitof them sliding with respect to each other. These members 1, 2 or 3, which are separate and. simply placed on each other, are carried by means of suitablesupports having preferably elastic movement, of which different forms of construction will be described later. I Thecasing,onceposition of the members-1, 21; and 3, is lined internally with suitable brasking. Thelining ,is designated L in Fig. 1 and-is shown partially" broken away;.in the other figure, the lining L is-not sliown formed by the placing in for. simplicity.

In order to compensate for the stresses dueto the de-* formation of the brasking, without however preventing" the movement of the walls 2 and 3, elastic means, such as springs 4,- are applied against the walls, the-said springs being supported on the members 5 of the fixed steel framework. The springs 4 are adjustable in such manner that the compression forces which they apply to the sides 2' and 30f the casing are amply proportioned with respectto the stresses produced by the deformation of the in-' terior brasking.

The details of the construction of the vat with Fig. 1 are shown in Figs. 2 and 3..\

On the foundation 6 consisting of a solid blocker-low walls of concrete, are mounted the members of .the. me-,

tallic framework which constitute the support forthe vat. These members consist of girders 7 spaced-apart.

and connected to upright members 8. The girders} which carry the plate 1 forming the base of the vat are mounted on the girders 7. The externally to the uprights 10.

On the base 1. is applied the bottom folded-in edge. 11 p of the sides 2. Each of these sides 2 is carried by a cradle 12 to which are fixed the supporting members 13. I

The latter are formed by elastic spring blades which are fixed to the cradle 12 at 14 and at their other extremities to the brackets 15 which are rigidly secured to the girders 9. This'assembly permits the sides 2 to have ahorizontal sliding movement without frictional contact. In an alternative form, the mobility'of the sides 2 may be obtained by mounting'the cradles 12 on rollers trav- 1 Patented-Nov;18,1958

in accordance girders 9 are rigidlly fixed to the longitudinal sides 2 (see Fig. 3) with their folded in edge 25 applied against the base 1 of: the vat. '1"-he side 3 is carried by the cradles. 17 which are themed-W8 supported on spring blades 18,- secured to angle-iron members 19 rigidly fixed to the girder 7. (or by rollers or slides). The cradles 1.7 are stayed, in opposition to the stresses due to. the deformation of the brasking, by means of springs 20. which are fixed to the upright; members ii, and which are. adjustable,

In order to carry out the adjustment; of the springs 16 (or 2i!) and, to keeptheir length within reasonable limits of space, the contact face 21 of the spring. is firmly secured to a. screw; 22 inserted in a threaded. sleeve 23 fixed to the support 10 (or 8). The screw 22. is provided with ausquare section 24 intended to receive the lever or the adjusting key.. In order to. check the adjustment of the springs. Hand 20, it. is an advantage to provide a gauge, rigidly fixed on the cradle 17 (or 12), the position ofjwhich, with respect to a fixed member such as the uprights 8; or 1 enables. the length of the spring to be -observed and. in. consequence the load which it carries, may be estimated. t

7 As shown on the drawing, the sides 2 and 3, supported by the cradles 12 and 17- capable of longitudinal movement have their edges 11. and. 25 overlaid on the base 1 which isfixedlon the girders 9. During. working, when the braslcing of the vat exerts alateral thrust, the sides). and 3 lendthemselves to deformation, whilst at the same time they are retainedby the springs 16 and 20.

In order to. permit of. this sliding movement of. the edges lland: 25 without the latter becoming displaced from the. basel by a dangerous amount, they are connectedto the base 1 in the manner shown in Figs. 4..and 5. Thesliding edge, 11 for example, is provided. with a series ofrivets 26, the. shanks 27 of which are engaged. in elongatedslots 283 formed in the base 1.. The head 29 of each rivet engages with a circular plate. 32 which is wider; than;,the slot 28. Thisplate 32 is retained. in position by. aspacing collar 31 fitted on the shank 27 of the rivet 2 6 With. this arrangement, the edge 11 slides over the base 1 in accordance with thenecessities of the deformation. of. the. brasking; withoutg ever. ceasing to be in contact. with the base. 1 and without however having to be subjected to. excessive. friction. At the. upper part of the vat, metal lips 33 and 34. are fi xed to the upper edge 'of the sides 2 and 3 and rest on the slabs 35 which form the service floor.

In the alternative form of embodiment shown in Figs. 6 and 7, the cradles12' and 17 are dispensed with. To the sides 2 and 3 of the vat are directly fixed supporting pillars which rest directly on the foundations. To each of the sides-2 is fixed a pillar 36, of which the free lower end 37 can be supported on a portion 38 of the concrete block 6, but without however being fixed in it. The pillars 36 of the two opposite sides 2 are coupled together by a tie-rod 39, the tension of which is adjustable. The tie-rod 39,,fixed on the pillar 37 at one side isfixed to the pillar 37 on, the other side to the intermediary of a calibrated spring 40. The tension of the spring. 40. is regulatedjby the nut 41 which screws on to the threaded end of the tie-rod 39.

In the form of construction shown, which comprises. two contiguous sets of pillars 37, there can be seen the symmetrically-mounted tie-rods of the two, pillars,, the

tie-rod of the second pillar being shown at 39- with. a spring on the opposite side to thespring 40. Each of the transverse sides is provided with a pillar 42, the lower end 43 of which is free. On the pillar 43 is mounted, through the intermediary of the spring 44, adjustable by the nut 45, a tie-rod 46. The other end of the tie-rod 46 is fixed to a member 47 which is attached to the steel framework 7.

The casing thus made up of elastically-sliding sides may be provided with orifices such as the slots 48, for

introduction of current-carrying bars, which are formed in the base 1 and, if this is necessary, in the sides 3. The reference number 49 indicates the assembly of rivets and elongated slots which couple the sides 2, 3 with the base 1 or with each other.

Instead of effecting the tensioning arrangements by tie-rods with adjustable springs, the tensile stresses of the tie-rods themselves may be employed, with the condition that these stresses are made to correspond to the zone of plastic deformation of the steel of which these tie-rods are made.

In this case, as is shown. in Fig. 8, the tie-rod 39 connecting two: pillars 37 is fixed to these pillars in a rigid manner at 50. The dimensions of. the tie-rod are chosen so.that under the pressure P which it is necessary to apply tothe walls of. the vat in order to obtain suitable cohesion of the linings, it is subjected to a stress F which corresponds to the point A of the stress-deformation curve for the metal (see Fig. 9), this point A being the elastic limitv of the metal employed.

From the moment at which the pressure P is reached, the walls of'the vat are. displaced outwards and the tierod. stretches, following theline AB of plastic deformation, without appreciable increasein the stress F applied to: the tie-rod. Nevertheless, the wall may move back so as. again to be located on the deformation curve A-B. If, for example, an accidental contraction of the brasking has taken place, the stress on the tie-rods falls awayi sharply and. the metal which has reached the point C in the zone of. plastic deformation, follows the path C-. -D parallel to O-A. When the wall again takes up its position, the metal follows the path DE and then continues its. elongation. along the portion E-D.

The displacement of. the. sides of the vat, retained in this. wayby tie-rods with controlled elastic limit, is

effected. under a substantially constant'stress by the elasticity. itself ofthe metal of the tie-rods which are of carefully selected steel. and the dimensions of which have been calculated to that end. The lining used in the vat is identical with that ordinarily employed in vats of the same kind. An example of such a lining can be found in Ur. 8.. Patent No. 2,593,751 to Grolee, issuedon April 22, 1952. Such lining forms no part of the invention, which is concerned exclusively with the framework of the vat.

What 1 claim is:

1'. Apparatus. for electro-rnetallurgy comprising a metallic casing having a carbonaceous lining and comprising five separate elements, namely, a flat bottom, and four sides slidably engaging said bottom, support means comprising means underlying and sustaining said fiat bottom, adjustable elastic means mounted on said support means and operatively engaging said sides for permiting movement of said sides relative to said bottom.

2. Apparatus for electro-metallurgy as in claim 1, and further comprising cradles supporting said sides,. and second support means carried by said first support means and connected to-said cradles; and permitting horizontal movement of said sides.

3. Apparatus for electro-metallurgy as in claim 2, said second support means. comprising flexible blades.

4. A vat as set forth in claim- 1, wherein the sides are provided with inturned. horizontal portions, which portions slide on the fiat bottom.

.5. A.vat= asset forth in claim 4, wherein the flat bottorn is provided with. elongated slots and the inturned portions are provided with rivets having the shanks there- References Cited in the file of this patent of slidably mounted in said SlOtS. FOREIGN PATENTS 6. A vat as set forth in claim 1, wherein the adjust- 1 01 545 F A 16 1952 able elastic means comprise a steel tie Tod having a conn "f' trolled elastic deformation and provide an elastic tension 5 between each pair of sides of the casing and at right angles to said sides. 

1. APPARATUS FOR ELECTRO-METALLURGY COMPRISING A METALLIC CASING HAVING A CARBONACEOUS LINING AND COMPRISING FIVE SEPARATE ELEMENTS, NAMELY, A FLAT BOTTOM, AND FOUR SIDES SLIDABLY ENGAGING SAID BOTTOM, SUPPORT MEANS COMPRISING MEANS UNDERLYING AND SUSTAINING SAID FLAT BOTTOM, ADJUSTABLE ELASTIC MEANS MOUNTED ON SAID SUPPORT MEANS AND OPERATIVELY ENGAGING SAID SIDES FOR PERMITTING MOVEMENT OF SAID SIDES RELATIVE TO SAID BOTTOM. 